The present invention relates to an air conditioner of a split type wherein an external unit having an external heat exchanger and an internal unit having an internal heat exchanger are disposed separately from each other, and respective heat exchangers are connected to each other by a refrigerant piping, to thus constitute a refrigeration cycle.
As the air conditioner of a split type wherein an external heat exchanger is connected to an internal heat exchanger by a refrigerant piping, for example, Japanese Patent Publication No. sho 57-31057 discloses an air conditioner of a split type which includes an external heat exchanger disposed outdoors, such as in a garden, and an internal heat exchanger disposed in the interior.
In such an air conditioner of a split type, since the internal heat exchanger and the external heat exchanger are disposed separately from each other, the length of the refrigerant piping for connecting the external heat exchanger to the internal heat exchanger becomes different depending upon the locations where these heat exchangers are disposed.
Also, since the diameter of the refrigerant piping is generally limited at a specified value, in the case that refrigerant is made to flow in the refrigerant piping, there is generated a specified passage resistance in the refrigerant piping. The resistance tends to increase in proportional to the length of the refrigerant piping.
Accordingly, when the resistance in the refrigerant piping is large, namely, the length of the refrigerant piping is long, the refrigerant circulating amount is sometimes reduced to be less than the designed value of the refrigeration cycle. This presents a problem that the refrigeration ability as designed cannot be obtained.
It may be considered to use a compressor having a large capacity in the refrigeration cycle and a receiver tank having a large capacity for achieving the high capacity. This makes it possible to cope with the situation when the refrigerant piping is long. The above attempt, however, is disadvantageous in that, for short refrigerant piping, the high capacity compressor and a large sized receiver tank are wasteful, and further, the internal unit and the external unit are made larger, thereby obstructing the miniaturization of these units.